If I am doing a full clean up (I'm not a sooper-dooper every weekend detailer like most of you), I usually start out with the interior. I work for a living, have a 45+ minute one-way commute and have other hobbies.
I try to vacuum out the interior once a month but that ends up usually being once every 3 months. Nonetheless, I like to get it over with and be fresh when doing it so that I do a good job. I use the household Dyson, all the attachments and will also have a couple of Libman brushes to help.
Interior glass and I don't use any sort of dash protectant. I don't want the greasy mess on everything and most of them...I despise the scent. And I've not seen an interior you need that stuff on since GM figured out that every other MFG's dash wasn't cracking.
Then, I hit the wheels first on the exterior. Once again, it's the toughest thing on the exterior and it's the last thing I want to do when I'm done with the exterior.